Abnormal hypermethylation in the promoter region of tumor suppressor gene RASSF1A (RAS associated domain family 1 A), repair gene MGMT, apoptosis-related genes EBF3 (Early B Cell Factor 3), cell cycle-related gene CDKN2B (Cyclin-dependent kinase inhibitor 2B) and other important genes often occurs in precancerous lesions or during the early carcinogenesis of tumors, inhibiting transcriptional activity and leading to tumor occurrence (40–42). This evidence concerns the gene MGMT and neoplasm.